Complex regional pain syndrome (CRPS), also called reflex sympathetic dystrophy syndrome and causalgia, is a chronic pain condition in which high levels of nerve impulses are sent to an affected site. Experts believe that CRPS occurs as a result of dysfunction in the central or peripheral nervous systems. CRPS is most common in people aged 20-35. The syndrome also can occur in children; it affects women more often than men.
In cases of injury-related CRPS, the syndrome may be caused by a triggering of the immune response which may lead to the inflammatory symptoms of redness, warmth, and swelling in the affected area. For this reason, it is believed that CRPS may represent a disruption of the healing process. Within the first 20 days, visual analogue scale (VAS) score decreased significantly more in the neridronate group. In the following 20 days, VAS remained unchanged in the placebo group and further decreased in the active group by 46.5 mm (95% CI -52.5, -40.5) vs 22.6 mm (95% CI -28.8, -16.3) for placebo group (P < 0.0001). Significant improvements vs placebo were observed also for a number of other indices of pain and quality of life. During the open-extension phase in the formerly placebo group the results of treatment were superimposable on those seen during the blind phase in the active group. A year later none of the patients was referring symptoms linked to CRPS-I.
One symptom of CRPS is continuous, intense pain that gets worse rather than better over time. If CRPS occurs after an injury, it may seem out of proportion to the severity of the injury.
Therapies used include psychotherapy, physical therapy, and drug treatment, such as topical analgesics, narcotics, corticosteroids, antidepressants and anti-seizure drugs. Other treatments include: Sympathetic nerve blocks, surgical sympathectomy, Intrathecal drug pumps, Spinal cord stimulation.